1. Field Of The Invention
The present invention relates to a data recording apparatus suitably used for digital audio tape recorder (DAT) and similar devices for the recording and reproduction of video and audio signals in the form of digital data on a magnetic tape as the magnetic recording medium.
2. Description Of The Prior Art
As a conventional recording reproducing apparatus there is known a digital audio tape recorder (DAT) in which an audio signal including a sound signal is converted into a digital signal for recording upon a magnetic tape. The audio signal is reproduced by converting the digital signal thus recorded upon a magnetic tape into the original audio signal. Some DATs of the type described above selection of an operating mode, either a two-channel mode in which two channels are set on a magnetic tape for individually recording thereon two kinds of audio signals or a four-channel mode in which four channels are set on a magnetic tape for individually recording thereon four kinds of audio signals.
For example, in a two-channel mode, the two kinds of audio signals corresponding respectively to two loudspeakers arranged in each of and on the right and left of an audience are recorded on the magnetic tape. In the case of a four-channel mode, the four kinds of audio signals correspond respectively to four loudspeakers arranged both in front of and behind as well as on the right and left of an audience are recorded on the magnetic tape.
Further, in the four-channel mode, there is also known in the art a DAT which employs a method for recording an audio signal in two of the four channels and a static video signal in the other two channels, allowing recorded audio and video signals to be reproduced from a single magnetic tape at the same time.
FIG. 1 is a view of a format of a magnetic tape 31 having thereon each of video data and audio data recorded in the four-channel mode. As shown in FIG. 1, audio data A are recorded continuously while video data V1 through V4 are intermittently recorded. When magnetic tape 31 is reproduced, a so-called presentation system capable of inserting a voice-over for every static picture can be realized.
JP-A 2-149991 (1990) discloses a recording apparatus for recording an video data and an audio data respectively upon a magnetic tape through the two-channel mode. In such a data recording and reproducing apparatus, the recording area for each of video and audio data is pre-set. Then, the video data or the audio data is recorded in each area.
In a recording and reproducing apparatus for recording data on the magnetic tape 31 having the format of FIG. 1, it is not possible to performing rewriting or "after-recording" (to record additional data to the recording medium) of an video data alone (or an audio data alone).
In the data recording and reproducing apparatus disclosed in JP-A 2-149991 (1990), the data are recorded on the magnetic tape using an original format of the apparatus, which leads to the problem of compatibility with other apparatus. In addition to this disadvantage, video data are separately recorded from the audio data even where the rewriting or after-recording of the data is not required. Because of this, it is necessary to prepare a memory for each of the video and the audio data where continuous and simultaneous reproduction of the data is required. Consequently, built-in memory in the data recording and reproducing apparatus must have relatively large capacity which also increases the size of the apparatus.